Residue from the sample can impact the sensitivity of the sensing bulb and clog the junction. This is especially true if the sample has a lot of organic material. Common signs that you need to clean the electrode are slow, drifting or erratic readings. You should proactively clean your pH electrode to prevent problems.
The procedure is simple. Soak the electrode in Milwaukee cleaning solution for 2-5 minutes for a routine clean or 20 minutes for a deeper clean. Make sure that the cleaning solution covers the junction.
Then rinse the probe with DI or distilled water to remove any cleaning solution residue. Use Distilled or DI water ONLY for washing and rinsing. Never submerge or store the probe in Distilled or DI water.
The probe then needs to be placed in storage solution for 2-3 hours before use.